Dry seal piston-type gas holder



May 19, 1953 J. H. WIGGINS DRY SEAL, PISTON-TYPE GAS HOLDER.

Filed April 1950 e o n o h o a a INVENTOR, JOHN H. WlGG/NS,

- ATTORNEY Patented May 19, 1953 UNITED STATES PATENT OFFICE DRY SEALPISTON-TYPE GAS HOLDER John H. Wiggins, Chicago, Ill.

Application April 6, 1950, Serial No. 154,357

6 Claims.

This invention relates to piston-type gas holders of the kind in whichthe annular space between the piston and the container side wall isclosed or bridged by a dry seal consisting of a flexible, curtain-likesealing means attached to said wall and piston and proportioned so as toprovide for the rise and fall of the piston. In conventional gas holdersof the general type or kind above referred to the dry seal between thepiston and the container side wall is constructed in whole or in partfrom fabric or some other suitable flexible material treated so as torender it gas-tight, and notwithstanding the fact that no expense isspared in the construction of such dry seals," there is always thepossibility of gases leaking through the same and combining with the airin the space above the piston to form an explosive mixture which createsa fire hazard.

The main object of my invention is to overcome or minimize the abovementioned inherent defect of conventional dry seal, piston-type gasholders. To this end I have devised a gas holder, which, in its simplestform, is composed of a container that constitutes a stationary portionof the gas storage chamber of the apparatus, a piston in said containerwhich is adapted to move relatively to the container so as to increaseor decrease the volume of the storage chamber, and a sealing means forthe piston, formed by a flexible, bag-like structure inflated with inertgas, bridging the space between the container and the piston andattached to said parts. The [particular shape of said gas-inflated,flexible, bag-like structure, or the way in which it is made, areimmaterial, so far as my broad idea is concerned, so long as it is ofsuch design or construction that it comprises at least two flexible,gas-tight wall portions or sealing elements, arranged in spaced oropposed relation and attached to the container and the piston, so as tobridge the space or joint between the same, one of said wall portions,which, for convenience, I will refer to as the inner seal, beingpresented to the gases in the storage chamber of the apparatus; and theother wall portion, referred to for convenience, as the outer seal beingpresented to the atmosphere, and a body of inert gas confined by andinterposed between said wall portions or sealing elements so astoprevent gases in the storage chamber that may leak through a defect orimperfection in the inner seal from becoming mixed with a body of airthat exists in a space adjacent to or at one side of the piston. Whilethe above described gas-inflated, multiple seal between the piston andthe container constitutes the basic feature of my present invention,another novel feature of my invention consists in combining such a,gas-inflated, multiple piston-sealing device with a means that isadapted to be operated, either manually or automatically, formaintaining the inert gas in said piston sealing device at a certainapproximate pressure. j

The figure of the drawings is a fragmentary, verticaltransverse-sectional view of a dry seal, piston-type gas holderconstructed in accordance with my invention.

Referring to said figure, A designates a container, provided with avertical side wall I of cylindrical form, and B designates averticallymovable, piston in said container that constitutes the topwall of the gas storage chamber of a gas holder, the peripheral edge ofsaid piston being spaced away a considerable distance from the side wallI of the container. The means used to seal the space or joint betweenthe piston and the container side wall consists of a flexible,gas-inflated, multiple wall device C of substantially tubular form ingeneral outline, attached to an intermediate portion of the containerside wall and to the periphery of the piston and bridging the gap orspace between said parts. It preferably is composed of two flexible,gas-impervious, annular wall portions 2 and 3, joined together at theiredges so as to form a tubular envelope or bag-like structure, whichconfines a body of inert gas X that holds said envelope in a distendedcondition. For convenience, I will refer to the wall portion 2 of saidenvelope or flexible, bag-like structure that is presented to the gasesY in the storage chamber of the apparatus, as the inner seal, and I willrefer to the other wall portion 3 of said bag-like structure that ispresented to the atmosphere, as the outer seal. During the cycle ofoperations of the piston, the gases Y in the storage chamber of theapparatus exert pressure on the above mentioned inflated envelope orbag-like piston sealing device C, in a direction to press one or theother wall portions or sealing elements 2 or 3 of said device into snugengagement, either with an annular back-stop member 4 rigidly attachedto the piston and projecting upwardly from the peripheral edge of same,or with the portion of the container side wall l, located above thepoint where said inflated piston-sealing device C is attached to thecontainer side wall, said back-stop member and container side Wallportion co-acting with each other to absorb pressure exerted on thepiston sealing device C by the gases in the storage chamber of theapparatus. Thus, as shown in full lines in the drawing, when the pistonB is at the end of its downward stroke, the sealing element 3 of theinflated piston sealing device snugly engages the back-stop member 4 onthe piston, and during the upward stroke of the piston, said device Cshifts into such a position that the sealing element 3 of same will bein snug engagement with the upper portion of the container side wall bythe time the piston reaches the end of'the upward stroke, as shown inbroken lines in the drawing. At all times, i. e., when the piston is inits lowermost position, uppermost position and intermediate position,the sealing element 2 of the inflated pistonrsealing device (I. ismaintained in spaced relation with the sealing element 3 by the inertgas X interposed between and confined by said sealing elements 2 and 3,thereby eiiectively preventing an explosive mixture from accumulating inthe air space above the piston B of the gas holder, inasmuch as the jint b t e n the p ston, and h erm ine id wall I is cl s d y a de ice G ht een r e e We u ularaped a n l ment 2. as i ar ranged in telescopedrelation and maintained a distended cond ion by a beer o in rt eainterposed between, andconiine dby said sealing elements.

Th bo o ine t see c nfi d betwe n t pposed Wall p r i n or s al n el mens 2 nd i. of. th piston sea in dev e (.1 is maintained ni der a certainapproximate pressure, preferably a pr s re e a to o reat han. t e p e suof the ases in the gas storage chamber. of the apparatus. This can beefiected either by man.- ually aryin the res ure. of the. n ga betweenthe seal ng filemel' s Z and, 3; rather wide intervals of time, say,for. example, once a week, or by automatically varying the pressure i ain rt see Space a the. inte a p es u e of the gas storage space of the,apparatus varies I also prefer to provide means for enabling the ert aac ef h pisto s a i dev ce C e purged atintervalf iri the event theinert gas between the sealin elements 2 and 1; becomes es ive y c nt mnated b s meat en f see Y through he i ner al n e ement n he embodimentof invention herein illustrated, a piston-type, auxiliary gas holder isused to au-I tcrnatically control the pressure or the body of inert gasX in the multiple seal, piston sealing device C. Said auxiliary gasholder is herein illustrated as comprising a container 5, a vertielvemevab ie e ii n aid c n ine an a flexible, curtain-like seal lattached to the piston and to the side wall of the container 5 so as to.divide the interior of the container into a pres: sure chamber 8 belowthe piston and an inert gas chamber 9 above the piston that contains asupply of inert gas. A conduit ii! leads from the said inert gas chamber9 to the inert gas space between the two sealing elements 2 and 3 of theiston sealing device C, and a conduit ll leads from the pressure chamber8 of the auxiliary gas holder to the lower end of the container A'inwhich the piston B operates, said conduits H1, and II being Wide open atall times. Preferably, the piston ii of the auxiliary holder is equip;-ped with a cc nt bal ne n mecha sm m.- prising a weight I2. If the loadof said weight just balances the piston 6, plus the piston seal i, thenthe pressure of the inert gas space between h ling elemen 2 and 3 o thep sten sea n device ,0 of the main gas olde w lvar rom o" t b u 2 a othe pr s re o t e ases, t r d n. he gee sta e-es hamber ei the mal gasholder, formed by the container A, piston B and inflated piston sealingdevice C. The initial pressure of the inert gas space of said pistonsealing device can be varied by varying, the weight of thecounterbalancing weight I2 of the auxiliary holder. The piston sealingdevice C is preferably provided with a manually-operated purging valve[3 that is adapted to be opened at relatively long intervals, say, forexample, from three months to nine months, so as to permit inert gas inthe space between the sealing elements and 3 of the piston sealingdevice C that has become contaminated by leakage of gas Y through thesealing element 2, to be replaced or replenished by fresh inert gas fromthe supply in the inert gas; chamber 9 of the auxiliary holder.

In the apparatus above described, if the pressure in the gas storagechamber of the main gas holder increases, then the pressure in the inertgas chamber s of the auxiliary holder is immediat 5 increased a d h nethe pr u e of the inertfgas between the sealing elements 2 and W i beiii te i sealin de e Q f h min holder s in reased There e s e m a on ofga Y threush the sea n el m 2 into he inert gas ace or the. sealing deve (1 bu this, s y slow and ee e dinsl t s e a widel h eed n er ls that ti n ee arr t purge, the ert, as space. o the. de ice Q his ene s the vale it a mul iel al see-i fla e p ston: sealin d Vi e f the kind, abovedescribed, th Outer seal n el ment 3 ta e eutetemielly ll of he, p essue. Of the. gas n the a st rage charm h r o the m in. olde the nn r ea in17 mee 2" y qr it mm W i t may take. hi ex eeen eeei re of t e inert eeX up to say, lieQ Will s a in filer meat 2 o hang s beieei e 1 like aertai w h portion r ame eurre l slight y he drew na.

havin time d serihe my in ent on, what el m snide-ere to. se ur Lett rsA ga holder eemlzri ne eenteiner havin e v r ica ide Well that f me. astat onery ies of t e eiereee ib-er of the ee ei'etue, avertieallyrmevatzle 1e sa d, ee tainen that amiable. Well o said eie eeethe-inn r a seal n devis for sa s n e osed pi air of subs antiallerlindiiee fiex i le e emen -e rr ged op ose re ation with t e r outer des att ch d to t e o tain r side w ll and th r nner e ges atta hed to hi ton a d a ody r inert as in rposed be ween a d onfined b t e pposed,newbie elements- 2-. a as h ld r the kind des ribe la m. providedwith ame ns n e operative by e ov ment o he is on o aid. con a ner for amatically main ain ng the inert. as twe n e o posed next 18 elements oaid pi to sea ins ev ce a ress re e ual o r r ater t an the pre sure thgase in t e et r se, ehembe f he epearatue- 3- A as holder. the ti edeser bed n, el im rrevieeew ih e s gin al e f r t e ne iee pace b twe nthe eieee d flexib e el' re is'e aid. piston. sealing de ice n means erenablin the in rt ee sa d s ace t e mainta ed at. e. e ie nap erimaierie se 2 An app ratus of the kind desc ibed is e a in P vid d wit an i et as s pp y r ser o r onnee ed y a conduit with he in rt s pat tween. heO po ed. fl ible e men s o i d'rien, s a ng d e. and. me. Nessie hlee-rise i to vary automatically as the pressure in the gas storagechamber of the apparatus varies.

5. The combination of a main gas holder, comprising a gas storagechamber Whose top wall is formed by a piston that reciprocatesvertically in a container having a side wall which surrounds and isarranged in spaced relation with the peripheral edge of said piston, asealing means for said piston formed by two substantially tubularspaced,telescoped, flexible sealing elements attached at their opposite ends tosaid stationary side wall and to said piston, respectively, andmaintained in spaced relation with each other by a body of inert gasconfined by said sealing elements, an auxiliary piston-type gas holderprovided with a pressure chamber and a dry gas chamber located abovesaid pressure chamber, a gas conduit that establishes communication atall times between the dry gas chamber of the auxiliary holder and thespace between the two flexible elements of the piston sealing means ofthe main holder, and a gas conduit that estab- JOHN H. WIGGINS.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,236,996 Ellis Apr. 1, 1941 FOREIGN PATENTS Number CountryDate 571M223 Germany Mar. 31, 1933

1. A GAS HOLDER, COMPRISING A CONTAINER HAVING A VERTICAL SIDE WALL THATFORMS A STATIONARY PORTION OF THE STORAGE CHAMBER OF THE APPARATUS, AVERTICALLY-MOVABLE PISTON IN SAID CONTAINER THAT FORMS A MOVABLE WALL OFSAID STORAGE CHAMBER, A SEALING DEVICE FOR SAID PISTON COMPOSED OF APAIR OF SUBSTANTIALLY CYLINDRICAL FLEXIBLE ELEMENTS ARRANGED IN OPPOSEDRELATION WITH THEIR OUTER EDGES ATTACHED TO THE CONTAINER SIDE WALL ANDTHEIR INNER EDGES ATTACHED TO THE PISTON, AND A BODY OF INERT GASINTERPOSED BETWEEN AND CONFINED BY THE OPPOSED FLEXIBLE ELEMENTS.